What Bluedriver Tests and What It Does Not

Bluedriver is a Bluetooth diagnostic scanner that plugs into your vehicle's OBD-II port (the diagnostic connector under your dashboard). It reads fault codes from your engine, transmission, and emissions systems — the same codes a mechanic's scanner reads. It does not perform physical tests on your battery or alternator the way a mechanic's multimeter does.

Bluedriver can tell you if your battery or alternator is failing because the engine computer has logged a fault code related to charging or voltage. For example, if your alternator is not charging properly, your engine control module will store a code like P0562 (system voltage too low). Bluedriver will display that code and explain what it means. But the scanner itself does not measure voltage, resistance, or current — it only reads what the vehicle's computer has already detected and stored.

If you want to know your battery's actual voltage or test whether your alternator is outputting the correct amperage, you need a separate tool: a digital multimeter or a dedicated battery/alternator tester. Bluedriver is a code reader and diagnostic tool, not a electrical testing device.

Key Takeaways

  • Bluedriver reads fault codes from your vehicle's computer related to charging, battery, and alternator problems — it does not physically test electrical components.
  • If your alternator or battery is failing, Bluedriver will show you the fault code your engine computer has logged, such as P0562 or P0563.
  • To measure actual voltage, amperage, or resistance, you need a multimeter or dedicated electrical tester in addition to Bluedriver.
  • Bluedriver works only on vehicles with an OBD-II port, which is standard on all cars sold in the United States since 1996.

How Bluedriver Detects Battery and Charging Problems

Your vehicle's engine computer monitors charging system voltage constantly. If the voltage drops too low (usually below 11.5 volts) or climbs too high (usually above 15.5 volts), the computer logs a fault code. Bluedriver reads these codes and displays them with a plain-language explanation.

Common charging-related codes Bluedriver will show you include P0562 (system voltage too low), P0563 (system voltage too high), P0622 (alternator field control circuit), and P0513 (incorrect immobilizer key). When Bluedriver displays one of these codes, it means your engine computer detected an electrical problem — but it does not mean Bluedriver measured the voltage itself. The computer did that; Bluedriver is just reporting what the computer found.

This is useful because it tells you something is wrong and points you toward the likely cause. But it does not replace a hands-on electrical test. A battery might be weak, an alternator might be failing, a serpentine belt might be slipping, or a corroded battery cable might be causing a voltage drop. Bluedriver narrows the field; it does not diagnose the exact component.

What You Need to Actually Test Battery and Alternator Output

To measure whether your battery is holding a charge or whether your alternator is outputting the correct voltage and amperage, you need a digital multimeter or a dedicated battery/alternator load tester. These are separate tools from Bluedriver.

A basic digital multimeter costs $15 to $50 and can measure DC voltage (to check battery voltage and alternator output), resistance (to test battery cables and connections), and sometimes amperage. A dedicated battery load tester costs $30 to $150 and simulates a load on the battery to see whether it can hold voltage under stress — a more realistic test than just measuring resting voltage.

If Bluedriver shows you a charging system fault code, the next step is to use a multimeter to measure your battery voltage (should be 12.6 volts at rest, 13.5 to 14.5 volts while the engine is running). If the voltage is low, you know the battery or alternator is the problem. Bluedriver got you to that point; the multimeter confirms which component is failing.

Bluedriver's Actual Strengths for Electrical Diagnosis

Bluedriver excels at reading and clearing fault codes, which saves you a trip to the mechanic for a basic diagnostic scan. If your check engine light is on, Bluedriver will tell you the code and what system it relates to — engine, transmission, emissions, or charging. For charging system problems, this is often enough to point you toward a battery or alternator replacement.

Bluedriver also provides live data streaming on some vehicles, which means you can watch real-time voltage readings from your engine computer as you drive or as someone revs the engine. This is more useful than a single code because you can see whether voltage is stable, climbing, or dropping. If voltage climbs to 15 volts when you rev the engine and then drops back to 13 volts at idle, your alternator is probably working but your battery might be weak. If voltage stays at 11 volts no matter what, your alternator is likely failing.

The live data feature is Bluedriver's closest equivalent to actual electrical testing — but it is still reading data from your vehicle's computer, not measuring with its own sensors. It is a useful diagnostic aid, but not a replacement for a multimeter.

When to Use Bluedriver Versus a Mechanic's Electrical Test

Use Bluedriver first if you want to know whether a fault code is stored and what it says. This costs nothing beyond the Bluedriver device itself (usually $100 to $150 one-time purchase) and takes five minutes. If a code is present, you have a starting point for repair.

Use a multimeter or load tester next if you want to confirm the battery or alternator is actually failing. This is a hands-on test that measures real electrical output and is more definitive than a fault code alone. If you do not own a multimeter, a mechanic can perform this test for $50 to $100 in diagnostic labor.

Use a mechanic's full electrical diagnostic if Bluedriver shows a charging code but your multimeter readings are normal, or if you want a professional to rule out wiring, connections, or less common causes like a faulty voltage regulator. A mechanic has specialized equipment and experience that Bluedriver cannot replace.

Bluedriver Limitations You Should Know

Bluedriver only works on vehicles with an OBD-II port, which is standard on all cars sold in the United States since 1996. If you own an older vehicle, Bluedriver will not connect. Some vehicles also have proprietary diagnostic protocols that Bluedriver cannot fully read — particularly some luxury and performance brands — so you may see fewer codes or less detail than a dealer scanner would show.

Bluedriver cannot test components that do not report to the engine computer. For example, if your battery terminals are corroded, the computer might not detect it because the voltage is still technically within range. A multimeter or visual inspection would catch this; Bluedriver would not. Similarly, if a serpentine belt is slipping, the alternator might not be spinning fast enough to charge properly, but the computer might not log a code until the voltage drops below the threshold.

Bluedriver is also not a substitute for a mechanic's experience. A fault code tells you what the computer detected, not necessarily what caused it. A P0562 code (low voltage) could mean a dead battery, a failing alternator, a loose battery cable, a bad ground, or a faulty voltage regulator. Bluedriver narrows it down; a mechanic's test and experience narrow it down further.

Frequently Asked Questions

Can Bluedriver tell me if my battery is dead?

Bluedriver can show you a fault code related to low voltage, which suggests a battery or charging problem. But it cannot measure your battery's actual voltage or state of charge. A multimeter or dedicated battery tester will tell you definitively whether your battery is dead or weak. If your battery is completely dead, Bluedriver may not power on at all because it draws power from your vehicle's 12-volt system.

Will Bluedriver show me if my alternator is failing?

Bluedriver will show you a fault code if your engine computer has detected a charging system problem, such as P0562 (voltage too low) or P0563 (voltage too high). These codes often point to alternator failure, but they can also indicate a weak battery, loose connections, or a bad voltage regulator. Use a multimeter to measure alternator output (should be 13.5 to 14.5 volts while the engine runs) to confirm.

Do I need Bluedriver if I already have a multimeter?

A multimeter tests electrical components; Bluedriver reads fault codes from your engine computer. They serve different purposes. A multimeter tells you voltage and resistance; Bluedriver tells you what codes are stored and provides live data from the computer. For charging system diagnosis, both tools together give you the most complete picture, but a multimeter alone is sufficient if you know what to test.

Can Bluedriver clear a battery or alternator fault code?

Yes, Bluedriver can clear fault codes from your engine computer. However, clearing a code does not fix the underlying problem. If your alternator is failing, clearing the P0562 code will not make it work. The code will return once you drive the vehicle and the computer detects the problem again. Clear codes only after you have repaired the actual component.

What is the difference between Bluedriver and a dealer diagnostic scanner?

A dealer scanner is a professional-grade tool that can read more codes, access more vehicle systems, and perform advanced tests like actuator controls and module programming. Bluedriver is a consumer-grade scanner that reads basic fault codes and provides live data on most vehicles. For most charging system problems, Bluedriver is sufficient; for complex electrical issues, a dealer scanner or mechanic is more appropriate.